A comparative study of appendicitis inflammatory response score and abdominal ultrasound in evaluation of patients with acute appendicitis at university teaching hospital of Kigali (CHUK)

Abstract

Background: Acute appendicitis is a common disease in surgical practice. Its usual presentation is often not classical, leaving a diagnostic problem in some cases. Using a scoring system that incorporates the inflammatory variables such as AIR score can improve and overcome this drawback. Aim of the study: To compare AIR score and abdominal U/S in evaluation of patients with acute appendicitis and to determine if AIR score can decrease the time and cost of care of patients with acute appendicitis. Patients and Methods: This prospective descriptive observational study included 42 patients who underwent appendectomy from June 2018 to May 2019. All parameters included in the AIR score and U/S results were collected and statistical analysis performed using SPSS version 21.0. Descriptive statistics and diagnostic performance of AIR score and U/S were compared. Results: We found 26 males and 16 females, M: F was 1.62:1. Age range was 7-55 years. Peak age: 26-35 years, with a mean of 31.26 years. The mean symptoms duration was 2.4 days. AIR score ranged from 5 to 12. 26 patients were classified into the indeterminate group and 16 patients into high-probability group. U/S request was associated with a longer mean time from admission to surgery (11 hours versus 5.3 hours). AIR score had a sensitivity and specificity of 43% and 100% respectively, while U/S had sensitivity and specificity of 92% and 20% respectively. AIR score demonstrated a higher specificity (100%) in high probability group while U/S showed a better sensitivity and specificity for indeterminate group of 94% and 100% respectively. U/S had a higher PPV (100%) than AIR score (86%) and AIR score showed a better NPV (67%) compared to U/S (19%). The ROC area of AIR score was 0.738 for AIR score and 0.562 for U/S (p = 0.09). Negative appendectomy rate was 11.9%. Conclusion: AIR score is more specific and accurate in high probability patients and also convincingly select patients who need abdominal U/S for diagnosis. Abdominal U/S is better at confirming the diagnosis or to rule out the possibility of appendicitis in equivocal cases.